Systems and methods for WiFi mapping in an industrial facility

ABSTRACT

Systems and methods for WiFi mapping an industrial facility are disclosed. The system comprises a self-driving vehicle having a WiFi transceiver. The self-driving vehicle communicates with a fleet-management using the WiFi transceiver, via a WiFi access point. The self-driving vehicle receives a mission from the fleet-management system, and moves to a destination location based on the mission, using autonomous navigation. While executing the mission, the self-driving vehicle simultaneously measures the received signal strength indication of the WiFi access point and other WiFi access points in the facility, and stores the received signal strength indication in association with the location at which the received signal strength indication was measured.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent ApplicationNo. 62/525,161 that was filed on 26 Jun. 2017, the contents of which areincorporated herein by reference for all purposes.

FIELD

The described embodiments relate to measuring and recordingenvironmental characteristics, and in particular, to WiFi mapping in anindustrial facility.

BACKGROUND

Autonomous vehicles represent significant advantages when used asmaterial transport vehicles within an industrial facility. Generally,these vehicles, individually or operating as a fleet, communicate witheach other, with fleet-management system, and with other ITinfrastructure using wireless communications. As such, the operation ofthe vehicles within the facility can be dependent on the ITinfrastructure installed within the facility.

In order to mitigate the likelihood of vehicle problems based on the ITinfrastructure, it is often necessary to understand the strength ofwireless communications signals within the facility. For example, asurvey can be performed to determine the strength of the communicationssignals prior to deciding that the IT infrastructure is suitable forsupporting a fleet of autonomous vehicles.

However, changes to the facility and the IT infrastructure can result inchanges to the strength of communications signals over time. As such, itmay be necessary to perform a subsequent survey, which can be costly andcumbersome. An effective means of continuously updating a survey ofcommunications signal strength is desired.

SUMMARY

In a first aspect, there is a system for WiFi mapping in an industrialfacility. The system comprises a self-driving vehicle that has a WiFitransceiver in communication with a fleet-management system via a firstWiFi access point. The self-driving vehicle has a drive system formoving the vehicle and a control system for autonomously navigating thevehicle. The control system has at least one non-transitorycomputer-readable medium and a processor. The medium stores instructionsthat, when executed, cause the processor to be configured to: receive amission comprising a destination location from the fleet-managementsystem via the WiFi transceiver; instruct the drive system to move thevehicle to the destination location based on autonomous navigation;determine a measurement location based on the autonomous navigation;receive a WiFi received signal strength indication via the WiFitransceiver associated with the measurement location; and store a valuebased on the received signal strength indication in association with themeasurement location on the at least one medium.

According to some embodiments, the instructions further compriseinstructions that, when executed, cause the processor to be configuredto: receive a second mission comprising a second destination locationfrom the fleet-management system via the WiFi transceiver; subsequent tothe vehicle moving to the destination location, instruct the drivesystem to move the vehicle to the second destination location based onautonomous navigation; subsequent to receiving the WiFi received signalstrength indication, receiving a second WiFi received signal strengthindication while the vehicle is in proximity of the measurementlocation; and replace the stored value with an updated value based onthe second received signal indication in association with themeasurement location.

According to some embodiments, the instructions further compriseinstructions that, when executed, cause the processor to be configuredto: determine a second measurement location based on the autonomousnavigation; receive a second WiFi received signal strength indicationvia the WiFi transceiver associated with the second measurementlocation; and store a second value based on the second received signalstrength indication in association with the second measurement locationon the at least one medium.

According to some embodiments, the instructions further compriseinstructions that, when executed, cause the processor to be configuredto: receive a second WiFi received signal strength indication via theWiFi transceiver associated with the measurement location; and store asecond value based on the second received signal strength indication inassociation with the measurement location. The received signal strengthindication pertains to the first WiFi access point and the secondreceived signal strength indication pertains to a second WiFi accesspoint.

According to some embodiments, the WiFi receiver is connected to thefirst WiFi access point and the WiFi receiver is not connected to theWiFi access point, and the second received signal strength indication isobtained by performing a background scan.

In a second aspect, there is a method for WiFi mapping in a facility.The method comprises moving the vehicle to a first destination locationbased on autonomous navigation. At a first time while moving the vehicleto the first destination location, a WiFi receiver of the vehicle isused to obtain a first received signal strength indication. A firstlocation of the vehicle based on the first time is determined, and avalue based on the first received signal strength indication is storedin association with the first location. The first destination locationis determined based on a first mission, and the first mission isindependent of obtaining the at least one received signal strength.

According to some embodiments, the method further comprises moving thevehicle to a second destination location based on autonomous navigation.At a second time when the vehicle is in proximity of the first location,the WiFi receiver is used to obtain a second received signal strengthindication. The stored first value is then replaced with a second valuethat is based on the second received signal strength indication inassociation with the first location. The second destination location isdetermined based on a second mission that is independent of the firstmission, independent of obtaining the first received signal strengthindication, and independent of obtaining the second received signalstrength indication.

According to some embodiments, the method further comprises using theWiFi receiver to obtain a second received signal strength indication ata second time while the vehicle is moving to the first destinationlocation. A second location of the vehicle is determined based on thesecond time. A second value based on the second received signal strengthindication is stored in association with the second location.

According to some embodiments, the method further comprises using theWiFi receiver of the vehicle to obtain a second received signal strengthindication during the first time, and storing a second value based onthe second received signal strength indication in association with thefirst location. The first received signal strength indication pertainsto a first WiFi access point and the second received signal strengthindication pertains to a second WiFi access point.

According to some embodiments, the WiFi receiver is connected to thefirst WiFi access point and the WiFi receiver is not connected to thesecond WiFi access point. Using the WiFi receiver to obtain the secondreceived signal strength indication comprises performing a backgroundscan on the second WiFi access point.

In a third aspect, there is a method for WiFi mapping in a facility. Themethod comprises receiving a mission from a fleet-management system witha self-driving vehicle. The mission has a destination location. Acurrent WiFi heat map of the facility is received. Based on the currentWiFi heat map, a preferred measurement location is determined. Thevehicle is moved to the preferred measurement location and thedestination location based on autonomous navigation. While moving thevehicle, a WiFi receiver of the vehicle is used to obtain a plurality ofsignal strength indications associated, respectively, with a pluralityof measurement locations. An updated WiFi heat map is stored based onthe current WiFi heat map, the plurality of signal strength indications,and the plurality of measurement locations associated with the signalstrength indications.

According to some embodiments, the preferred measurement location isdetermined based on the current WiFi heat map and the destinationlocation.

According to some embodiments, the current WiFi heat map comprisesvalues associated with locations in the facility. Storing the updatedheat map comprises storing updated values based on the plurality ofsignal strength indications.

In a fourth aspect, there is a method for determining environmentalcharacteristics with a self-driving vehicle. The method comprises movingthe vehicle to a first destination location based on autonomousnavigation. At a first time while moving the vehicle to the firstdestination location, at least one sensor of the vehicle is used toobtain a first measurement of at least one environmental characteristic.A first location of the vehicle is determined based on the first time.The first measurement is stored in association with the first location.The first destination location is determined based on a first missionthat is independent of sensing the at least one environmentalcharacteristic.

According to some embodiments, the method further comprises moving thevehicle to a second destination location based on autonomous navigation.At a second time when the vehicle is in proximity of the first location,the at least one sensor of the vehicle is used to obtain a secondmeasurement of the at least one environmental characteristic. The storedfirst measurement is replaced with the second measurement in associationwith the first location. The second destination location is determinedbased on a second mission that is independent of sensing the at leastone environmental characteristic and the first mission.

According to some embodiments, the at least one sensor is a WiFireceiver, the at least one environmental characteristic comprises afirst WiFi signal from a first WiFi access point, and the firstmeasurement is a first signal strength measurement of the first WiFisignal and the second measurement is a second signal strengthmeasurement of the first WiFi signal.

BRIEF DESCRIPTION OF THE DRAWINGS

A preferred embodiment of the present invention will now be described indetail with reference to the drawings, in which:

FIG. 1 is a system diagram of a self-driving material-transport vehicle,according to some embodiments;

FIG. 2 is a plan view of a facility in which a system for measuring andrecording environmental characteristics can be deployed, according tosome embodiments;

FIG. 3 is a plan view of the facility of FIG. 2 depicting the system formeasuring and recording environmental characteristics at a timesubsequent to the time in FIG. 2;

FIG. 4 is a map of the values of the measurements obtained in FIG. 3;

FIG. 5 is a plan view of the facility of FIG. 2 depicting the system formeasuring and recording environmental characteristics at a timesubsequent to the time in FIG. 3;

FIG. 6 is a map of the values of the measurements obtained in FIG. 5;and

FIG. 7 is a flow diagram depicting a method for measuring and recordingenvironmental characteristics, according to some embodiments.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

Referring to FIG. 1, there is shown a self-driving material-transportvehicle 100 according to some embodiments. The vehicle comprises a drivesystem 102, a control system 104, and one or more sensors 106, 108 a,and 108 b.

The drive system 102 includes a motor and/or brakes connected to drivewheels 110 a and 110 b for driving the vehicle 100. According to someembodiments, the motor may be an electric motor, combustion engine, or acombination/hybrid thereof. Depending on the particular embodiment, thedrive system 102 may also include control interfaces that can be usedfor controlling the drive system 102. For example, the drive system 102may be controlled to drive the drive wheel 110 a at a different speedthan the drive wheel 110 b in order to turn the vehicle 100. Differentembodiments may use different numbers of drive wheels, such as two,three, four, etc.

According to some embodiments, additional wheels 112 may be included (asshown in FIG. 1, the wheels 112 a, 112 b, 112 c, and 112 d may becollectively referred to as the wheels 112). Any or all of theadditional wheels 112 may be wheels that are capable of allowing thevehicle 100 to turn, such as castors, omni-directional wheels, andmecanum wheels.

The control system 104 comprises a processor 114, a memory 116, and acomputer-readable non-transitory medium 118. The controls system 104 isin communication with (or includes) a communications transceiver 120 forcommunications with other systems, such as a fleet-management system.Generally speaking control systems in self-driving vehicles comprisecommunications transceivers; and the communications transceiver 120 isspecifically included in FIG. 1 due to the relevance of the transceiver120 as a type of sensor for sensing environmental characteristics, asfurther described herein.

One or more navigational sensors 106, 108 a, and 108 b may be includedin the vehicle 100. For example, according to some embodiments, thenavigational sensor 106 may be a LiDAR device (or other optical/laser,sonar, or radar range-finding sensor). The navigational sensors 108 aand 108 b may be optical sensors, such as video cameras. According tosome embodiments, the navigational sensors 108 a and 108 b may beoptical sensors arranged as a pair in order to provide three-dimensional(e.g. binocular or RGB-D) imaging.

The control system 104 uses the medium 118 to store computer programsthat are executable by the processor 114 (e.g. using the memory 116) sothat the control system 104 can provide automated or autonomousoperation to the vehicle 100. Furthermore, the control system 104 mayalso store an electronic map that represents the known environment ofthe vehicle 100, such as a manufacturing facility, in the media 118.

For example, the control system 104 may plan a path for the vehicle 100based on a known destination location and the known location of thevehicle. Based on the planned path, the control system 104 may controlthe drive system 102 in order to drive the vehicle 100 along the plannedpath. As the vehicle 100 is driven along the planned path, thenavigational sensors 106, and/or 108 a and 108 b may update the controlsystem 104 with new images of the vehicle's environment, therebytracking the vehicle's progress along the planned path and updating thevehicle's location.

Since the control system 104 receives updated images of the vehicle'senvironment, and since the control system 104 is able to autonomouslyplan the vehicle's path and control the drive system 102, the controlsystem 104 is able to determine when there is an obstacle in thevehicle's path, plan a new path around the obstacle, and then drive thevehicle 100 around the obstacle according to the new path.

According to some embodiments, the vehicle 100 may receive a missionfrom a fleet-management system or other external computer system incommunication with the vehicle 100 (e.g. in communication via thetransceiver 120). In this case, the mission contains one or morewaypoints or destination locations. Based on the waypoint or destinationlocation contained in the mission, the vehicle 100, based on the controlsystem 104, can autonomously navigate to the waypoint or destinationlocation without receiving any other instructions from an externalsystem. For example, the control system 104, along with the navigationalsensors 106, and/or 108 a, and 108 b, enable the vehicle 100 to navigatewithout any additional navigational aids such as navigational targets,magnetic strips, or paint/tape traces installed in the environment inorder to guide the vehicle 100.

In addition to using the communications transceiver 120 forcommunicating with other systems, such as a fleet-management system, thevehicle 120 may use the transceiver 120 as a receiver or sensor in orderto measure the signal strength of a communications signal as anenvironmental characteristic. Furthermore, the vehicle 100 may includeone or more additional environmental sensors 122.

As used here, the term “transceiver”, “receiver” and “sensor” may all beused to refer to a device that detects environmental characteristics. Inparticular, a “transceiver” necessarily includes a “receiver”, and theseterms denote devices that detect communications signals (i.e.electro-magnetic waves) within an environment.

According to some embodiments, the transceiver 120 may be a WiFi™transceiver, thereby including a WiFi receiver. According to someembodiments, the transceiver 120 may utilize other wirelesscommunications schemes, for example, a cellular communication scheme.

According to some embodiments, the additional environmental sensors 122may comprise any or all of another wireless transceiver (e.g. WiFi,cellular), a thermal sensor for measuring temperature, an optical orphoto sensor for measuring light (e.g. ambient light), a humidity sensorfor measuring relative humidity, chemical-absorbent sensors formeasuring airborne toxin levels, and radiation sensors. Generally, thesystems and methods described here can be used to determine signallevels of communications signals such as WiFi within an industrialfacility; as well as other environmental characteristics that may berelevant to worker safety, product quality, process efficiency, andoperations of the facility.

The communications transceiver 120 and the other environmental sensors122 are in communication with the control system 104. As such, thecontrol system 104 may receive data from the environmental sensors 120and 122. Furthermore, according to some embodiments, the control system104, including the processor 114, the memory 116, and thecomputer-readable non-transitory medium 118, may be configured toperform the methods described herein. For example, the medium 118 maystore computer-readable instructions that, when executed by theprocessor 114, cause the processor 114 to be configured to perform themethods. According to some embodiments, any or all of the methods may beperformed by either or both of the control system 104 and afleet-management system in communication with the control system 104.

According to some embodiments, the processor 114 may produce a productthat is stored on the medium 118 and/or on a fleet-management system,that includes a map of the measured environmental characteristics inassociation with, or independent of the electronic map of the facilitythat is used by the control system 104 in the autonomous navigation ofthe vehicle 100.

Referring to FIG. 2, there is shown a facility 200 in which a system formeasuring and recording environmental characteristics can be deployedaccording to some embodiments. The facility 200, as shown, is an exampleof an industrial manufacturing facility. The facility 200 generallycomprises an inventory area 210 having a shelf 212 for storing inventoryitems, a machining area 214 having a machine 216 for doing work on aworkpiece, a work room 218, and a finished goods area 220.

A self-driving vehicle 222 operates within the facility 200 in order toprovide various material-transport tasks within the facility 200.Generally, the self-driving vehicle is capable of autonomous navigation,as previously described. The vehicle 222 may fulfill tasks according tomissions assigned by a fleet-management system 224. As shown in FIG. 2,the fleet-management system 224 is connected to a WiFi access point 224.Three other WiFi access points 226, 228, and 230 are located in thefacility 200, enabling a communications network in which the vehicle 222can communicate with the fleet-management system 224 or other vehiclesthroughout the facility 200.

As used here, the term “WiFi” refers generally to any wirelesslocal-area networking technology and protocols. For example, WiFi mayrefer to systems and protocols that employee an IEEE 802.11 standard.

In an example depicted in FIG. 2, the fleet-management system 224 hassent a mission to the vehicle 222 to pick up a workpiece 232 from theshelf 212, and deliver it to the machine area 214 so that the workpiececan be machined by the machine 215. As such, the mission includes adestination location 234 adjacent to the shelf 212.

The dotted line 236 indicates the travel path of the vehicle 222 sinceit received its mission from the fleet-management system 224. As shown,the vehicle 222 has autonomously navigated around a finished-goods area238 and towards the destination location 234.

According to some embodiments, as the vehicle 222 is moving towards thedestination location 234, it is continuously, intermittently,periodically, or arbitrarily using its environmental sensors to obtainmeasurements of environmental characteristics throughout the facility200. According to some embodiments, the measurements may be takenperiodically (i.e. according to frequency of measurements), or based onthe vehicle 222 traveling a particular distance since the lastmeasurement was obtained. According to some embodiments, each dot of thedotted line 236 represents a different measurement location at which ameasurement was obtained.

According to some embodiments, the vehicle 222 uses its WiFi receiver todetermine a received signal strength indication at the dot 240. Forexample, the vehicle 222 may have been connected (i.e. communicatingdigital information with) the access point 230, and therefore may havereceived a signal strength indication from the access point 230 at themeasurement location 240. As the vehicle 222 travelled along the line236, it may have subsequently dropped its connection with the accesspoint 230 in order to connect with other access points. For example, thedot 242 may represent a measurement location at which the vehicle 222was connected to the access point 224.

As used herein with respect to WiFi transceivers and WiFi access points,the term “connected” means that the WiFi transceiver and WiFi accesspoint are communicating with each other using a digital communicationsprotocol; which does not require a mechanical connection.

According to some embodiments, the vehicle 222 may obtain measurementsof more than one environmental characteristics at a single measurementlocation. For example, at measurement location 240, the vehicle 222 mayhave obtained received signal strength indication from the access point230 to which it was connected, as well as receiving a signal strengthindication from the access point 228. According to some embodiments,while connected to the access point 230, the vehicle may obtain areceived signal strength indication from the access point 228 byperforming a background scan.

According to some embodiments, the vehicle 222 may associate eachobtained measurement with the time at which the measurement wasobtained.

Referring to FIG. 3, there is a is shown the facility 200 at a timesubsequent to that shown in FIG. 2. As shown, subsequent to picking upthe workpiece at the destination location 234, the vehicle 222 hastravelled to the destination location 344 in order for the workpiece 232to be machined by the machine 216, and is transporting the workpiece 232to the finished-goods area 238. The dotted line 336 indicates the travelpath of the vehicle 222 since it received its mission from thefleet-management system 224.

As shown, after picking up the workpiece 232 at the first destinationlocation 234, the vehicle 222 started moving back, approximately, alongits path to the destination location 234. In doing so, the vehicle 222obtained measurements at new measurement locations in the inventory area210, and also moved over previously-used measurement locations.According to some embodiments, a measurement location may be defined interms of an area (e.g. a proximity to a particular measurement locationpoint) such that, when the vehicle 222 is within the area (i.e. withinproximity) of a previously-used measurement location, the subsequentmeasurement obtained at that measurement location may be associated withthe previously-used measurement location rather than a new measurementlocation.

For example, according to some embodiments, the measurement location 342may be deemed to be sufficiently close to the measurement location 242such that the measurement obtained at the dot 342 is associated with thesame measurement location as the measurement previously obtained at thedot 242.

According to some embodiments, when a measurement is obtained at apreviously-used measurement location, each measurement obtained at themeasurement location may be associated with the time at which themeasurement was obtained. In this way, differences in measurements takenat the same location but at different times can be determined in orderto identify variances in the environmental characteristics. According tosome embodiments, statistics can be determined over time for theenvironmental characteristics at a particular location based on otherobtained measurements that are adjacent in time and/or space.

At the time shown in FIG. 3, the vehicle 222 may have been connected toany or all of the WiFi access points 224, 226, 228, and 230 at sometime, and/or obtained background scan information from them. As comparedto the time shown in FIG. 2, in FIG. 3, the vehicle 222 has made moremeasurements (e.g. one for each dot in the line 336). Generally, as thevehicle 222 travels through the facility 200, it obtains moremeasurements of the environmental characteristics (e.g. WiFi receivedsignal strength indications). According to some embodiments, eachmeasurement is stored (e.g. on the vehicle's control system or othercomputer) in association with the corresponding measurement location.

Referring to FIG. 4, there is shown a map 400 of the values of themeasurements obtained in FIG. 3 in respect of the facility 200.According to some embodiments, the values may be stored in a datastructure, in association with locations relative to the facility 200,on the vehicle's control system or another computer system such as afleet-management system or another computer terminal connected thereto.According to some embodiments, a visual heat map may be generated anddisplayed by a computer terminal that includes displaying a visuallayout of the facility 200 overlaid with the values of the obtainedmeasurements.

As depicted, the values shown represent the obtained measurements ofenvironmental characteristics normalized on a scale of one to ten. Otherunits and scales may be used. For example, WiFi signals may berepresented in decibels. In the example of FIG. 4, question marks “?”are used to indicated that no measurements have been obtained for theassociated locations.

The map 400 may be referred to as a “heat map”. Generally, the exampleof FIG. 4 shows a heat map in the form of a grid with relativelylarge-scale grid lines. This is for the sake of example and description.According to some embodiments, a heat map may be generated based on aresolution commensurate with the distribution (in time or space) of themeasurements. According to some embodiments, the heat map may beconsidered as comprising discrete regions (e.g. a grid) with a value foreach region that is based on one or more obtained measurements withinthat region. According to some embodiments, the value for a region maybe determined by statistics applied to a sample of the measurementsobtained from within the region.

According to some embodiments, the map may be in the form of atessellation that may comprise polygons such as triangles,quadrilaterals, pentagons, hexagons, heptagons, octagons, etc. Forexample, a tessellation may be used to support a triangulated irregularnetwork.

The example map 400 indicates that the values for received signalstrength indications are generally higher in locations that are closerto a WiFi access points.

According to some embodiments, more than one value may be associatedwith a point or region on the map, corresponding to more than oneenvironmental characteristic. For example, each grid in the map 400could have a value represented in the form {N₁, N₂, N₃, N₄, t},referring, respectively to the received signal strength indications fromeach of the WiFi access points 224, 226, 228, and 230, and the time atwhich the received signal strength indications were obtained. Accordingto some embodiments, the time may be recorded as a single time thatapproximates the sequence of times at which each received signalstrength indication was received. According to some embodiments, aseparate time may be recorded for each received signal strengthindication.

According to some embodiments, a map may be derived in a similar manneras the map 400 based on differences and variations in the map over timerather than the obtained values themselves. In other words, if multiplevalues are obtained at a particular location or time (or adjacent to orin proximity of the location), and the obtained measurements arerecorded with their associated times of measurement, then a map can bederived based on the differences over time. According to someembodiments, a difference threshold may be determined such that, if thedifference between obtained measurements at a particular location exceedthe threshold, a notification can be made with respect to the map sothat a human user can be notified to investigate the change.

According to some embodiments, a map may be derived based on statistics,interpolations, and/or extrapolations of the obtained measurementsrather than the obtained measurements themselves. For example, atriangulated irregular network may be used.

Referring to FIG. 5, there is shown the facility 200 at a timesubsequent to that shown in FIG. 3. As shown, the vehicle 222 hasexecuted multiple missions, and travelled to multiple destinationlocations, thereby obtaining measurements from throughout the facility200. This is represented by the increased number of dots (i.e. dottedlines marking the paths of the vehicle 222) as compared to FIG. 3.

The scene depicted in FIG. 5 has several differences from the scenes inFIG. 3 and FIG. C (though not all differences are represented visually).In particular, the workpiece 232 is located in the finished-goods area238 rather than the shelf 212; and there are several workpieces in thefinished-goods area. The doors of the work room 218 are closed. Themachine 216 is operating, including the operation of a high-speedelectric motor.

According to some embodiments, the autonomous navigation of the vehicle222, including its path planning and obstacle-avoidance capabilities mayresult in travel paths (i.e. the distribution of the dots in FIG. 5)that are more distributed than would be possible using a moredeterministic means of material transport. In other words, since themeasurements are obtained by self-driving vehicles according toautonomous navigation, over time, the spatial distribution of themeasurement locations will be proportionate to the likelihood of avehicle being in the associated part of the facility. On one hand, thevehicle 222 is unlikely to follow the exact same path twice in a row. Onthe other hand, there are certain regions of the facility that will bemore frequently travelled. For those regions of the facility that arenot frequently travelled, fewer measurements will be obtained; but theinherent interest of those measurements will be lower.

Referring to FIG. 6, there is shown a map 600 of the values of themeasurements obtained in FIG. 5 in respect of the facility 200.Reflective of the distinctions between the scenes of FIG. 5 and thescenes of FIG. 2 and FIG. 3, there are corresponding differences betweenthe heat map 600 in FIG. 6 and the heat map 400 in FIG. 4.

All of the value question marks (“unknown”) in the map 400 have beenreplaced with numerical values. According to some embodiments, this maybe because the vehicle 222 has passed through all of the squares in thegrid during a previous mission. According to some embodiments, a valuemay be assigned to a square in the grid (e.g. to a location on the map)by using on an interpolation or estimation based on the values in othersquares in the grid (e.g. at other locations on the map) along with, orin the absence of obtained measurements from within the square.

The value in the square to the right of the destination location 234 hasbeen changed from a “6” in the map 400 to a “7” in map 600. It may beinferred that the geometry and/or materials of the workpiece 232attenuated the WiFi signal from the access point 226, and thus, removingthe workpiece 232 from the shelf 212 resulted in an increase in thereceived signal strength indication at the map location.

The value in the square above the finished-goods area 238 has beenchanged from a “?” in the map 400 to a “5” in map 600. At first glance,it may appear that this merely a known value replacing a state of“unknown”. However, upon closer inspection, it can be seen that thevalue “5” appears to be lower than expected, since three of the fouradjacent squares contain a value of “7”. (E.g. the expected value forthe square above the finished-goods area 238 may be been “6” rather than“5”). Thus, an inference may be drawn that the workpieces that have beenplaced in the finished-goods area 238 are attenuating the WiFi signalsfrom the access points 228 and 230.

The values for the squares corresponding to the machine area 214 are “1”and “2”, which appear to be significantly lower than expected. Aninference may be drawn, or further investigation may reveal that thehigh-speed electric motor of the machine 216 is causing interferencewith the WiFi signal from the access points 226 and 228.

Furthermore, the squares that are two-above and three-above thefinished-goods area 238 appear to be lower than expected. These valuesmay be effected by the attenuation of the WiFi signals from the accesspoints 228 and 230 by the workpieces in the finished goods area 238 incombination with the interference caused by the operation of the machine216.

Similarly, the value of “1” in the center square may be a result ofseveral factors, including the interference caused by the operation ofthe machine 216, the closed doors of work space 218, and the workpiecesin the finished-goods area 238.

Referring to FIG. 7 there is shown a method 700 for WiFi mapping of anindustrial facility, and, more generally, for measuring and storingenvironmental characteristics. According to some embodiments, the method700 may be stored as computer instructions stored on non-transitorycomputer-readable media on any or all of a self-drivingmaterial-transport vehicle, a fleet-management system, and an enterpriseresource planning system. Each of the vehicle, fleet-management system,and enterprise resource planning system include at least one processorand memory such that the computer instructions can be used to configurethe processors to execute any or all of the steps of the followingmethods.

The method begins at step 710 when the vehicle receives a mission fromthe fleet-management system. Generally, the vehicle communicates withthe fleet-management system using the vehicle's WiFi transceiver,through one or more WiFi access points within the facility. The missionincludes one or more destination locations to which the vehicle is to bemoved.

At step 712, a determination is made with respect to the missionpriority and whether there are any preferred locations for obtainingmeasurement. According to some embodiments, if an existing heat mapincludes areas that have a low density of obtained measurements (interms of time and/or space), or a relatively long time has passed sincethe most-recent measurement was obtained for a location, then thevehicle may be sent to particular locations in order to obtainmeasurements. In other words, in some cases, it is possible to navigatethe vehicle based on the current state of the heat map, in order togather data to update and populate the heat map itself.

According to some embodiments, a mission priority may be determined. Themission priority represents the availability for the vehicle to travelto locations that would otherwise be unnecessary for the mission,without jeopardizing the mission itself. For example, some missions maybe time-critical, and there may be insufficient time available for avehicle to deviate from the shortest path to the destination locationwhile still satisfying the mission. Other missions may not betime-critical such that the vehicle is available to travel to preferredmeasurement locations on its way to the destination location.

At step 714, the vehicle autonomously navigates and moves towards thedestination location. For example, the mission may stipulate that thevehicle is to pick up a workpiece from a storage location and deliver itto a machine cell. In this case, the destination locations may be thestorage location and the location of the machine cell. In accordancewith the mission, the vehicle moves towards the destination location. Inthe case of a mission including multiple destination locations, thismeans moving towards the next destination location specified by themission.

In the event that a determination was made at step 712 that the vehicleshould be sent to locations in order to obtain measurements at thoselocations, then at step 714, the vehicle may navigate through preferredmeasurement locations while navigating towards the destination location.According to some embodiments, the mission may be altered to include thepreferred measurement locations as intermediate “destination locations”.According to some embodiments, the vehicle's control system may navigatethrough the preferred measurement locations on the way to thedestination location without altering the mission itself.

At step 716, while the vehicle is executing the mission, theenvironmental sensors on the vehicle measure the environmentalcharacteristics along the vehicle's travels. According to someembodiments, the WiFi receiver on the vehicle measures the receivedsignal strength indication as the vehicle is travelling along itsplanned path to the destination location. In this way, the self-drivingvehicle is simultaneously accomplishing two separate and unrelatedgoals. First, it is performing the mission as provided by thefleet-management system. Second, it is gathering data with respect toenvironmental characteristics in the facility. For example, the vehiclecan determine the WiFi received signal strength indication as it travelsthrough the facility, while simultaneously (and independent from)performing it's primary role as a material-transport vehicle.

According to some embodiments, at step 716, the vehicle may obtain morethan one measurement at a particular location or time (or within aproximity of a particular location or time). According to someembodiments, for a particular measurement location (or within aproximity thereof), the vehicle may obtain one measurement of aparticular environmental characteristic, and another measurement ofanother environmental characteristic. For example, the vehicle mayobtain a temperature measurement and a humidity measurement. Forexample, the vehicle may obtain a received signal strength indicationfrom a first WiFi access point and another received signal strengthindication from a second WiFi access point.

At step 718, the measurement (e.g. WiFi received signal strengthindication) obtained at step 716 is stored in association with thelocation at which the measurement was obtained. According to someembodiments, the measurement is stored on a non-transientcomputer-readable medium, for example, that is a part of the vehicle'scontrol system. According to some embodiments, the measurement is storedin terms of a map (e.g. “heat map”) in which the value of themeasurement is stored with respect to the measurement location on themap. According to some embodiments, the measurement and associatedlocation are transmitted to the fleet-management system and stored onthe fleet-management system.

At step 720, the vehicle continues to move towards the destinationlocation according to its autonomous navigation. According to someembodiments, step 720 is illustrated in FIG. 7 in order to describe thatthe measurements are obtained while the vehicle is simultaneously movingand navigating with respect to the mission. According to someembodiments, the measurements may be obtained regardless of whether thevehicle actually moving or navigating at any particular instant, andregardless of whether the vehicle is at the destination location or onits way to the destination location.

According to some embodiments, at step 722, the vehicle may obtainanother measurement at another measurement location on its way to thedestination location. According to some embodiments, the vehicle mayobtain measurements periodically (in time) or after a pre-determineddisplacement (in space) as it travels along its planned path to thedestination location. At step 724, the measurements taken at step 722are stored in association with their respective measurement locations,similar to as described for step 718.

The vehicle eventually arrives at the destination location. At step 726,a determination is made as to whether there are other destinationlocations specified in the mission, or whether another mission is to bereceived by the fleet-management system. The method proceeds to any ofsteps 710, 712, 714, and 728 accordingly.

In the event that another destination location is specified in themission, the method returns to step 712 or 714 as indicated by thedashed lines. In the event that the vehicle receives another mission,the method returns to step 710. For subsequent destination locationsand/or missions, the vehicle will either obtain measurements at newmeasurement locations within the facility, or it will obtainmeasurements at (or in proximity of) previously-used measurementlocations.

In the event that a subsequent measurement is obtained in associationwith a previously-used measurement location, the subsequent (new)measurement may be stored in association with the measurement location.According to some embodiments, the new measurement may be stored inplace of (i.e. replace, by deleting) the previously-stored measurement.According to some embodiment, more than one measurement, taken atdifferent times, may be stored for the same location. According to someembodiments, more than one measurement may be used to determine astatistical value for the environmental characteristic at a particularlocation, for example, by taking different measurements over time at thesame location, and/or by using measurements taken at adjacent or nearbylocations.

The present invention has been described here by way of example only.Various modification and variations may be made to these exemplaryembodiments without departing from the spirit and scope of theinvention, which is limited only by the appended claims.

We claim:
 1. A system for operating one or more self-driving vehiclesfor WiFi mapping in an industrial facility, the system comprising: aself-driving vehicle having a WiFi transceiver in communication with afleet-management system via a first WiFi access point; the self-drivingvehicle having a drive system for moving the self-driving vehicle and acontrol system for autonomously navigating the self-driving vehicle; thecontrol system having at least one non-transitory computer readablemedium and a processor, the at least one medium storing instructionsthat, when executed, cause the processor to be configured to: receive amission data comprising a destination location and a mission priorityfrom the fleet-management system via the WiFi transceiver; determine apath to the destination location; determine at least one preferredmeasurement location, wherein the at least one preferred measurementlocation comprises a location associated with at least one of a numberof data points below a minimum data point threshold and data pointsassociated with a measurement date that is older than a minimummeasurement frequency threshold; determine whether modifying the path toinclude the at least one preferred measurement location would cause theself-driving vehicle to exceed a mission completion time determinedbased on the mission priority; in response to determining the modifiedpath would not cause the self-driving vehicle to exceed the missioncompletion time, modify the path to include the at least one preferredmeasurement location as an intermediate location; instruct the drivesystem to move the self-driving vehicle along the modified path to thedestination location based on autonomous navigation; receive a WiFireceived signal strength indication via the WiFi transceiver when theself-driving vehicle is in proximity of the at least one preferredmeasurement location; and store a value based on the received signalstrength indication in association with the at least one preferredmeasurement location on the at least one medium.
 2. The system of claim1, wherein the instructions further comprise instructions that, whenexecuted, cause the processor to be configured to: receive a secondmission data comprising a second destination location from thefleet-management system via the WiFi transceiver; subsequent to theself-driving vehicle moving to the destination location, instruct thedrive system to move the self-driving vehicle to the second destinationlocation based on autonomous navigation; subsequent to receiving theWiFi received signal strength indication, receive a second WiFi receivedsignal strength indication when the self-driving vehicle is in proximityof the at least one preferred measurement location; and replace thestored value with an updated value based on the second received signalindication in association with the at least one preferred measurementlocation.
 3. The system of claim 1, wherein the instructions furthercomprise instructions that, when executed, cause the processor to beconfigured to: receive a second WiFi received signal strength indicationvia the WiFi transceiver when the self-driving vehicle is remote to theat least one preferred measurement location; determine a measurementlocation associated with a location of the self-driving vehicle when thesecond WiFi signal strength indication is received; and store a secondvalue based on the second received signal strength indication inassociation with the measurement location on the at least one medium. 4.The system of claim 1, wherein the instructions further compriseinstructions that, when executed, cause the processor to be configuredto: receive a second WiFi received signal strength indication via theWiFi transceiver when the self-driving vehicle is in proximity of the atleast one preferred measurement location; and store a second value basedon the second received signal strength indication in association withthe at least one preferred measurement location; wherein the receivedsignal strength indication pertains to the first WiFi access point andthe second received signal strength indication pertains to a second WiFiaccess point.
 5. The system of claim 4, wherein the WiFi receiver isconnected to the first WiFi access point and the WiFi receiver is notconnected to the second WiFi access point; and the second receivedsignal strength indication is obtained by performing a background scan.6. A method for WiFi mapping in a facility with one or more self-drivingvehicles, the method comprising: receiving a mission data from afleet-management system, the mission data comprising a destinationlocation and a mission priority; determining a path to the destinationlocation; determining at least one preferred measurement location,wherein the at least one preferred measurement location comprises alocation associated with at least one of a number of data points below aminimum data point threshold and data points associated with ameasurement date that is older than a minimum measurement frequencythreshold; determining whether modifying the path to include the atleast one preferred measurement location would cause the self-drivingvehicle to exceed a mission completion time determined based on themission priority; in response to determining the modified path would notcause the self-driving vehicle to exceed the mission completion time,modifying the path to include the at least one preferred measurementlocation as an intermediate location; moving the self-driving vehiclealong the modified path to the destination location based on autonomousnavigation; during operation of the self-driving vehicle along themodified path, using a WiFi receiver of the self-driving vehicle toobtain a received signal strength indication when the self-drivingvehicle is in proximity of the at least one preferred measurementlocation; and storing a value based on the received signal strengthindication in association with the at least one preferred measurementlocation.
 7. The method of claim 6, further comprising: receiving asecond mission comprising a second destination location from afleet-management system; moving the self-driving vehicle to the seconddestination location based on autonomous navigation; when theself-driving vehicle is in proximity of the at least one preferredmeasurement location, using the WiFi receiver to obtain a secondreceived signal strength indication; replacing the stored first valuewith a second value based on the second received signal strengthindication in association with the at least one preferred measurementlocation.
 8. The method of claim 6, further comprising: using the WiFireceiver to obtain a second received signal strength indication when theself-driving vehicle is remote to the at least one preferred measurementlocation; determining a measurement location of the self-driving vehiclecorresponding to a location of the self-driving vehicle when the secondreceived signal strength indication is obtained; and storing a secondvalue based on the second received signal strength indication inassociation with the measurement location.
 9. The method of claim 6further comprising: using the WiFi receiver of the self-driving vehicleto obtain a second received signal strength indication when theself-driving vehicle is in proximity of the at least one preferredmeasurement location; and storing a second value based on the secondreceived signal strength indication in association with the at least onepreferred measurement location; wherein the first received signalstrength indication pertains to a first WiFi access point and the secondreceived signal strength indication pertains to a second WiFi accesspoint.
 10. The method of claim 9, wherein the WiFi receiver is connectedto the first WiFi access point and the WiFi receiver is not connected tothe second WiFi access point; and using the WiFi receiver to obtain thesecond received signal strength indication comprises performing abackground scan on the second WiFi access point.
 11. A method foroperating one or more self-driving vehicles for WiFi mapping a facility,the method comprising: receiving, with a self-driving vehicle, a missiondata from a fleet-management system, the mission data having adestination location and a mission priority; determining a path to thedestination location; receiving a current WiFi heat map of the facility;determining at least one preferred measurement location based on thecurrent WiFi heat map, wherein the at least one preferred measurementlocation comprises a location associated with at least one of a numberof data points below a minimum data point threshold and data pointsassociated with a measurement date that is older than a minimummeasurement frequency threshold; determining whether modifying the pathto include the at least one preferred measurement location would causethe self-driving vehicle to exceed a mission completion time determinedbased on the mission priority; in response to determining the modifiedpath would not cause the self-driving vehicle to exceed the missioncompletion time, modifying the path to include the at least onepreferred measurement location as an intermediate location; moving theself-driving vehicle along the modified path to the destination locationbased on autonomous navigation; during operation of the self-drivingvehicle along the modified path, using a WiFi receiver of theself-driving vehicle to obtain a plurality of signal strengthindications associated respectively with a plurality of measurementlocations, wherein the plurality of measurement locations comprises theat least one preferred measurement location when the self-drivingvehicle is in proximity of the at least one preferred measurementlocation; and storing an updated WiFi heat map based on the current WiFiheat map, the plurality of signal strength indications, and theirassociated plurality of measurement locations.
 12. The method of claim11, wherein the at least one preferred measurement location isdetermined based on the current WiFi heat map and the destinationlocation.
 13. The method of claim 11, wherein the current WiFi heat mapcomprises values associated with locations in the facility, and storingthe updated WiFi heat map.
 14. A method for determining environmentalcharacteristics in a facility with one or more self-driving vehicles,the method comprising: receiving a mission data from a fleet-managementsystem, the mission comprising a destination location and a missionpriority; determining a path to the destination location; determining atleast one preferred measurement location, wherein the at least onepreferred measurement location comprises a location associated with atleast one of a number of data points below a minimum data pointthreshold and data points associated with a measurement date that isolder than a minimum measurement frequency threshold; determiningwhether modifying the path to include the at least one preferredmeasurement location would cause the self-driving vehicle to exceed amission completion time determined based on the mission priority; inresponse to determining the modified path would not cause theself-driving vehicle to exceed the mission completion time, modifyingthe path to include the at least one preferred measurement location asan intermediate location; moving the self-driving vehicle along themodified path to the destination location based on autonomousnavigation; during the operation of the self-driving vehicle along themodified path, using at least one sensor of the self-driving vehicle toobtain a measurement of at least one environmental characteristic whenthe self-driving vehicle is in proximity of the at least one preferredmeasurement location; and storing the measurement in association withthe at least one preferred measurement location.
 15. The method of claim14, further comprising: receiving a second mission comprising a seconddestination location from a fleet-management system; moving theself-driving vehicle to the second destination location based onautonomous navigation; when the self-driving vehicle is in proximity ofthe at least one preferred measurement location, using the at least onesensor of the self-driving vehicle to obtain a second measurement of theat least one environmental characteristic; replacing the stored firstmeasurement with the second measurement in association with the at leastone preferred measurement location.
 16. The method of claim 15, wherein:the at least one sensor is a WiFi receiver; the at least oneenvironmental characteristic comprises a first WiFi signal from a firstWiFi access point; and the measurement is a first signal strengthmeasurement of the first WiFi signal and the second measurement is asecond signal strength measurement of the first WiFi signal.
 17. Themethod of claim 14, further comprising: using the at least one sensor ofthe self-driving vehicle to obtain a second measurement of the at leastone environmental characteristic when the self-driving vehicle is remoteto the at least one preferred measurement location; determining ameasurement location of the self-driving vehicle associated with alocation of the self-driving vehicle when the second measurement of theat least one environmental characteristic is obtained; and storing thesecond measurement in association with the measurement location.
 18. Themethod of claim 14, wherein the at least one environmentalcharacteristic comprises a first environmental characteristic and asecond environmental characteristic.
 19. The method of claim 18,wherein: the at least one sensor is a WiFi receiver; the firstenvironmental characteristic is a first WiFi signal from a first WiFiaccess point, and the second environmental characteristic is a secondWiFi signal from a second WiFi access point; and the first measurementis a first signal strength measurement of the first WiFi signal and thesecond measurement is a second signal strength measurement of the secondWiFi signal.
 20. The method of claim 19, wherein the WiFi receiver isconnected to the first WiFi access point and the WiFi receiver is notconnected to the second WiFi access point; and using the WiFi receiverto obtain the second measurement comprises performing a background scanon the second WiFi access point.